Many consumer products are applied to the skin or hair, and/or involve the sensory experience of touching. Consumer preferences are influenced by a multitude of factors, including product effectiveness, the feel of the product, fragrance, durability, ease of rinsing, etc. One way to determine consumer preferences is by conducting consumer marketing tests, in which a representative group of consumers, or panelists, provide feedback after using a product. Consumer marketing tests have several drawbacks, however. Because panelists must be appropriately selected and compensated for their time, such tests are expensive and time consuming. Human feedback is inherently subjective, and may raise concerns about reliability. Products must be safe for human testing, and the analyses that can be performed after application also are limited.
Some product testing can be performed using model systems. Artificial substrates are available that, to some extent, imitate human skin. For example, theatrical performers often transform their appearance by using molded body parts that can be made to look remarkably like human skin. Alternatively, keratinous tissue from animals or human cadavers may be used. Whereas these and other available models may be suitable for some types of product testing, all have significant limitations. Cadaver tissue is costly, and neither cadaver nor animal tissue truly mimics various types of living, human tissue. Artificial substrates are poorly suited to assess characteristics such as product adsorption, rinseability, elasticity and compressibility. Many substrates absorb water and/or decompose, and thus cannot be effectively cleaned or reused. Currently available models also fail to reflect differences in skin on various parts of the body, in different environments, and between different individuals, which may be critical in developing certain personal care products. Characteristics of skin on, for example, one's face, fingertips, palms of the hand, heels, and underarms tend to differ dramatically. The skin of babies and young children differs from the skin of adults, and skin having hair differs from non-haired skin.
There exists a need, therefore, to reduce testing with human subjects and to broaden the range of product testing that can be performed, by providing a method of using a substrate having properties of mammalian keratinous tissue to reproduce a range of properties most relevant to a given product.